The present invention relates to an aluminum alloy fin material for heat-exchanger with high thermal conductance. It relates, in more detail, to an aluminum alloy fin material to be used for fins of radiator being a heat-exchanger for cars, heater, condenser and the like produced particularly by brazing method.
The majority of heat-exchangers for cars uses Al or Al alloy and is produced by brazing method. Usually, for brazing, Al-Si type filler alloy is used, hence the brazing is performed at high temperature of around 600.degree. C. In the heat-exchangers of radiator etc., as shown in FIG. 1 for example, a thin-wall fin (2) machined in corrugated shape is formed unitedly between a plurality of flat tubes (1), both ends of said flat tubes (1) open respectively in spaces constituted by header (3) and tank (4), high-temperature refrigerant is fed from the space of one tank side to the space of other tank (4) side through flat tubes (1), thereby heat-exchanging at the portions of flat tube (1) and thin-wall fin (2), and the refrigerant having become low temperature is circulated again.
Now, recently, the heat-exchanger is in the direction of lightening in weight and miniaturizing, and, for this, improved thermal efficiency of heat-exchanger is required and improved thermal conductance of material is desired. In particular, improved thermal conductance of fin material is investigated and a fin material of alloy with alloy composition brought close to pure aluminum is proposed as a high-thermal conductance fin. When thinning the fin, however, there are problems that, if the strength of fin is insufficient, then the fin collapses on assembling of heat-exchanger or it ends up to break on using as a heat-exchanger. In particular, in the case of pure aluminum type alloy fin, it has a drawback of insufficient strength, hence a fin with high strength and improved thermal conductance has not yet been developed. This is because of that the addition of alloy elements such as Mn is effective for high strength or, since the production process includes brazing to heat near 600.degree. C., the elements added to alloy form the solid solution during brazing to hinder the improvement in thermal conductance.
In view of this situation, the inventors considered that, for developing a fin material with high strength and thermal conductance after soldering, the problems could be solved, if improving the thermal conductance by making the quantities of Si and Fe appropriate and further if possible to find the alloy elements having significant improvement effect on strength without decreasing the thermal conductance, leading to the invention.